Magnetic chuck



Patented Feb. 10, 1948 UNITED STATES PATENT OFFICEv MAGNETIC CHUCK Charles D. Briggs, Worcester, Mass., assignor to O. S. Walker 00. Inc., Worcester Mass, a corporation of Massachusetts Application January- 15, 1944; Serial No. 518,316

I 4 Claims. 1.

This invention relates to magnetic chucks Whether electric orpermanent magnetic and to separate top plates in combination therewith.

Objects of the invention include the provision of:- achuck body having contained therein a source of magnetic flux and designed to provide a; surface comprising two soft iron members magnetically spaced along predetermined lines for the purpose of supporting and magnetically holding separate, removable, and interchangeable top plates, said top plates each comprising a-pair ofsoft iron members magnetically spaced in conformance with the magnetic separation or gap'appearing in the above mentioned surface andadapted to be aligned therewith for cooperation with the magnetic flux source for the purpose of arranging the lines of flux to provide pluralities of work holding means, whereby the chuck body may be used with various top plates of different pole patterns to hold many varied work pieces.

Further objects of the invention include the provision-of agenerally U-shapedsoftiron boxlike frame, containing a source of magnetic flux, the space between the free ends of the U being closedv by a solid soft ironplate magnetically spaced fromsaid arms, the top surface of said plate being in linewith the free ends of the arms; thisdevice forming a source of flux which is capable. of carrying interchangeable top plates ofvaried configuration as to the pole pieces, said'top platesbeing easily separabletherefrom.

Other objects and advantages of the invention. will be hereinafter described.

In the drawings,

Fig. 1 is. aview in end elevation of oneform of the invention, parts being insection.

2 is a partial top plan view of one form of'top plate showing various pole patterns.

Fig. 3 is a view similar to Fig. 2 showing different pole patterns, parts being in section.

Fig. 4 is a top plan view of the chuck body with parts broken away and taken on line 4-4 of Fig. 1, and

Fig. 5 is a top plan view of the chuck body arranged'for receiving an electric coil.

In Fig. 1 there is shown a generally U-shaped soft iron body having a bottom I0 and upstanding'jfree endedlegs l2. The bottom in and legs IZ-may be castintegrally or may be built up in parts and-securedtogether. A source of magnetic-flux is placed-within the chuck body and for the purposeof illustration in Fig. 1 this is shown as a pair of-fixed permanent magnets in bar form as shown at l4. At central rotatable magnet I6 is provided to rotate on an axis at I81. and" this. magnet can bev journaled in end plates not shown. The bottom I0 is formed with av circular depression 20. to accommodate the rotary magnet; Magnets l4 rest directly on the bottom It. but are magnetically spaced from arms I? by non-magnetic material as at 22.

A solid soft iron plate 2 3 is placed on magnets id for direct magnetic connection therewith'and this plate is hollowed out at 26 similarlyto the depression 2'9 and. for the same purpose.

The construction as so far described provides a source of magnetic flux or magnetic battery in which the flux in on position of the control traverses the gap 22 which is rectangular in form in the'surface of the chuck body as is shown in Fig. 4, and as it stands will hold any iron pieces crossing these gaps.

Various forms of top plates may beset directly on the top surface'of the magnetic battery and one such top plate is disclosed in Fig. 1. This to plate comprises a plate: 28 having a series of holes therethrough, these holes being in communication with an interior recess indicated at 30. The recess 36 conforms in general to the shape of plate 28 but appears at the lower side only thereof and has an areadefined by the interior aspect of arms l2 of the chuck body.

A pole plate 32 having upstanding poles 34 designed to conform to the holes in plate28 is set into recess 30 with the pole pieces *34 in the holes as clearly shown in Fig. l. Non-magnetic materialsfi is cast between plates 28 and 32-so as to effectively separate these two members. Pole pieces 35 may be-sepa-rate as-shown or integral with plate 24.

The flux from the magnets will travel through plate 24 into all of the poles 34, and work pieces spanning the gaps 38 occasioned by the none magnetic material 35 will obviously be held to the top plate. The pole pattern of the top plate may be considerably varied as illustrated in Fig. 2 in which square and oblong pole pieces Mare shown, these pole piecesbeing spaced from the plate 28 by gaps 42; However the construction in effect is the same as above described and it is to beunderstood that the pole pattern may assume any design desired as long as the gaps 36 coincide with gaps 22 at the mating lower surface of the top plate and upper surface of the chuck body.

In Fig. 5 I show a box-like frame similar to that shown in Fig. 1 but having a. soft iron core M for the reception of an electric coil not shown. In this case plate 24 is used but without the depression 25' and the construction and operation of the device is otherwise the same as that above described.

It will be seen thatthe'presentinvention dis- 3 closes a magnetic chuck or battery which may be either permanent or electric and which utilizes separable and interchangeable top plates having a variety of pole patterns, as long as the top plate, of whatever pole pattern, has a gap construction similar to that at 36 for alignment with the gap 22; and thus articles of greatly differing sizes and shapes may be held to the chuck throughout the entire top surface thereof,

eliminating the necessity of providing a different chuck for different work pieces, and decreasing the need for special chucks, special work holders, and auxiliary and supplemental top plates.

Having thus described my invention and the advantages thereof, I do not wish to be limited to the details herein disclosed, otherwise than as set forth in the claims, but what I claim is:

1. In a device of the class described, a soft iron housing forming a box-like structure and comprising a bottom member, connected side walls thereon, and a substantially solid top fitted between the side walls and magnetically insulated therefrom, a source of magnetic flux adapted to energize the bottom and side walls under one sign and the top under the opposite sign, and a separate removable and replaceable top plate comprising a pair of soft iron members magnetically insulated along a line conforming to the magnetic insulation between the solid top and side walls, one soft iron member being in the form of a rim adapted to coincide with the top edges of the side walls, and the other soft iron member being inside the rim and of a size and shape to coincide with the solid top, said soft iron members together presenting a work holding surface, said inside soft iron member comprising a plate having a lower element substantially entirely of soft iron in magnetic contact with said solid top, and said rim member having solid soft iron portion extending through and across the inside member, said portions being magnetically insulated from the inside member, and projections in the inside member extending to the top surface thereof between and insulated from said portions.

2. In a device of the class described, a soft iron housing forming a box-like structure and comprising a bottom member, connected side walls thereon, and a substantially solid top fitted between the side walls and magnetically insulated therefrom, a source of magnetic flux adapted to energize the bottom and side walls under one sign and the top under the opposite sign, and a separate removable and replaceable top plate comprising a pair of soft iron members magnetically insulated along a line conforming to the magnetic insulation between the solid top and side walls, one soft iron member being in the form of a rim adapted to coincide with the top edges of the side walls, and the other soft iron member being inside the rim and of a size and shape to coincide with the solid top, said soft iron members together presenting a work holding surface, said inside member comprising a lower soft iron element in magnetic contact with the solid top and spaced projections rising from the element, said projections being surrounded at their sides with magnetic insulation, said rim member having soft 'iron portions extending across and above the said lower element and filling the spaces between the projections, the latter having their top surfaces coplanar with the top surface of the rim member and the said portions thereof.

3. In a device of the class described, a soft iron housing forming a box-like structure and comprising a bottom member, connected side walls thereon, and a substantially solid top fitted between the side walls and magnetically insulated therefrom, a source of magnetic flux adapted to energize the bottom and side walls under one sign and the top under the opposite sign, and a separate removable and replaceable top plate comprisin a pair of soft iron members magnetically insulated along a line conforming to the magnetic insulation between the solid top and side walls, one soft iron member being in the form of a rim adapted to coincide with the top edges of the side walls, and the other soft iron member being inside the rim and of a size and shape to coincide with the solid top, said soft iron members together presenting a work holding surface, said inside member being located below the top surface of the rim member and being apertured, soft iron members in the apertures and projecting members thereabove into co-planar relation with the rim member, magnetic insulation about each projection and covering the inside member, said rim member extending across and above the inside member and forming therewith and the projections a flat parallel sided solid plate, the inside member only of which is in magnetic contact with the said solid top.

4. In a device of the class described, a soft iron housing forming a box-like structure and comprising a bottom member, connected side walls thereon, and a substantially solid top fitted between the side walls and magnetically insulated therefrom, a source of magnetic flux adapted to energize the bottom and side walls under one sign and the top under the opposite sign, and a separate removable and replaceable top plate comprising a pair of soft iron members magnetically insulated along a line conforming to the magnetic insulation between the solid top and side walls, one soft iron member being in the form of a rim adapted to coincide with the top edges of the side walls, and the other soft iron member being inside the rim and of a size and shape to coincide with the solid top, said soft iron members together presenting work holding surface, said rim member having a recessed bottom surface conforming in area to the solid top and extending completely across the same in spaced relation thereto due to the recess, the recessed area being apertured, the inside member being located in the recess and in magnetic contact with the solid top and projections on the inside member rising into the apertures and terminating in a co-planar relation with the rim member top surface, said rim member being magnetically insulated from the inside member and its projections.

CHARLES D. BRIGGS.

REFERENCES CITED The following references are file of this patent:

UNITED STATES PATENTS of record in the 

